The creator of Nickelodeon's long-running hit, SpongeBob SquarePants, says he has been diagnosed with Lou Gehrig's disease.

Stephen Hillenburg told Variety that he will continue to work on the show for as long as he's able.

“I wanted people to hear directly from me that I have been diagnosed with ALS.,” Hillenburg said in a statement to the trade paper. “Anyone who knows me knows that I will continue to work on SpongeBob SquarePants and my other passions for as long as I am able. My family and I are grateful for the outpouring of love and support. We ask that our sincere request for privacy be honored during this time.”

Lou Gehrig's disease, also known as ALS for amyotrophic lateral sclerosis, is a progressive neurodegenerative disease that attacks nerve cells in the brain and the spinal cord.that control the muscles. It is a rare illness, with no known cure.

The 55-year-old Hillenburg is a former marine biology teacher who created the SpongeBob series, featuring an animated sponge that lives in Bikini Bottom in a pineapple under the sea, in 1999. The endearing animation, featuring a cast of goofy characters, started as a Saturday morning cartoon, then became a primetime multibillion-dollar franchise popular with kids and adults, spawning animated and live-action movies and even a stage musical.

Hillenburg also directed 2004’s The SpongeBob SquarePants Movie, and was the co-writer and executive producer on the 2015 sequel, The SpongeBob Movie: Sponge out of Water. He stepped down as a showrunner from the series for a decade before returning in 2014 as an executive producer.

Last March, Nickelodeon renewed SpongeBob for a 10th and 11th season, which will keep the series on the air for well over 200 episodes.

Nickelodeon said in a statement to Variety that Hillenburg "is a brilliant creator who brings joy to millions of fans" and that the network's "thoughts and support" are with Hillenburg and his family.